This invention relates generally to aircraft oil flow systems, and more specifically to a system for managing oil flow from an aircraft engine during normal and inverted flight.
During operation of an internal combustion engine, a gaseous mixture of unburned fuel and other exhaust gases is directed out of the engine. This gaseous mixture also frequently includes small amounts of oil that was used to lubricate mechanical components of the engine. Although much of this gaseous mixture is directed out of the engine using an exhaust pipe, a portion of this gaseous mixture is often not directed to the exhaust pipe and remains in the engine. In aircraft, the portion of the gaseous mixture not directed through the exhaust pipe is commonly directed out of the engine and using a breather tube that has an opening outside of the fuselage of the aircraft. While this configuration prevents degradation of engine performance, oil in the gaseous mixture is frequently deposited on exterior surfaces of the aircraft when directed out of the breather tube during flight. Because of flight speeds and airflow around the fuselage, small amounts of oil in the gaseous mixture may be spread across large areas of the aircraft fuselage, causing streaking or other areas of discoloration that may be difficult to remove.
In some configurations, the gaseous mixture from the engine is directed to an air/oil separator before being expelled from the aircraft. The air/oil separator removes oil from the gaseous mixture while directing the gaseous components outside of the aircraft. However, conventional oil separators store oil separated from the gaseous mixture in the separator itself, so changes in aircraft orientation reposition the oil in the air/oil separator, causing some of the stored oil to be directed out of the aircraft, and onto the fuselage, via the breather tube along with gaseous components. For example, during inverted flight oil stored in the air/oil separator transitions to a different surface of the air/oil separator, so a portion of the stored oil to be captured by the flow of the gaseous components and to be directed outside of the aircraft.